Some portable electronic devices comprise transducers such as loudspeakers and/or earpieces which are required to be small in size. Transducers are important components in electronic devices such as mobile phones for the purposes of playing back music or having a telephone conversation. The quality and loudness of a transducer in an electronic device are important especially if a user listens to sounds generated by an electronic device at a distance from the electronic device.
Furthermore in portable devices dust and water protection is important specifically with regards to the transducers. However dust and other small particles (and water) can often reach the transducer components and cause component damage. In particular the dynamic moving coil components in transducers radiate in each direction as the diaphragm moves forwards and backwards and as the construction of the transducer typically has open outlets on either side of the transducer which are free to air and the permanent magnet of a moving coil transducer can attract magnetic particles which migrate through the portable device and reach the coil and diaphragm. These particles can damage the sensitive components and/or reduce the performance of these components when the apparatus is in operation.
For example after some time the force between magnetic dust on the diaphragm and the permanent magnet inside the electrodynamic loudspeaker can pull the diaphragm towards the magnet and make the sound quieter, cause distortion or both. These types of failure typically requires repair and are costly to the manufacturer of the device if the failure occurs within the warranty period. Furthermore these features can cause brand damage if the failure occurs soon after the warranty period as the user considers the device to have failed prematurely and of poor quality.